Complete ScrollingFrame Sizing?

How do I get a more accurate CanvasSize from an ScrollingFrame? Note that all the buttons that get added the frame overtime are (0, 25, 0, 25).

Currently, my size code is this:

if #Frame2:GetChildren() ~= 0 then
	script.Parent.CanvasSize = UDim2.new(0, 0, 0, #Frame2:GetChildren()*30)--what i have right now, not working.
end

On line 01 and 02, you are using the :GetChildren() method. GetChildren() is a read-only array of the parents properties, Use the pairs function.

for _,Frames in pairs(Frame:GetChildren()) do
	if #Frames ~= 0 then
		script.Parent.CanvasSize = UDim2.new(0, 0, 0, #Frames*30)
	end
end